cremeglace writes: Whether for online bills or military secrets, encryption schemes help keep digital communication secure. In recent years, physicists and engineers have been developing methods that transmit uncrackable encode messages in individual particles of light, or photons. Now, one team has taken such quantum cryptography a long step forward by demonstrating a system that’s fast enough to encrypt a video transmission. “From the applications point of view, it’s very important,” says Hoi-Kwong Lo, a physicist at the University of Toronto in Canada.